Five-time former presidential candidate and activist Ralph Nader has said Hillary Clinton is winning the Democratic nomination by “dictatorship”, and that Donald Trump will defeat himself and “turn the Republican Party into the Trump Dump.”

Speaking to US News, Nader highlighted issues that billionaire Trump has brought to the public’s attention, including trade agreements and challenging Wall Street.

“I don’t know how authentic that is,” Nader said of Trump’s claims to have challenged Wall Street.

While Nader commended Trump’s campaign for not being run on donations, he was critical of Trump’s behavior on the campaign trail: “He's lowered the level of political debate to unheard-of depths of salacious, slanderous and vacuousness, garnished with massive self-boosterism and repetition."

When asked to comment on the positives in Clinton’s campaign, Nader pulled no punches, describing her as a “corporatist, militarist Democrat" who would have been beaten by Sanders were it not for closed primaries and superdelegate “cronies”.

"She's going to win by dictatorship,” Nader said. “Twenty-five percent of superdelegates are cronies, mostly. They weren't elected. They were there in order to stop somebody like Bernie Sanders, who would win by the vote."

Nader was referring to the origins of superdelegates, set up by the DNC in 1982 to ensure the massive losses of Democratic presidential nominees George Mc Govern and Jimmy Carter would not happen again.

Or, in the words of DNC chair Debbie Wasserman Schultz: “Unpledged delegates exist really to make sure that party leaders and elected officials don’t have to be in a position where they are running against grassroots activists.”

Speaking to CNN in April, Nader said Sanders should continue to run, pointing to the fact that Clinton could be hit by another scandal such as the contents of her Wall Street speeches coming to light.

Nader was accused of being a ‘spoiler’ candidate in the 2000 presidential election which saw Democratic candidate Al Gore lose to Republican George W Bush.

Nader, who ran as a Green Party nominee, was blamed for taking votes away from the Democratic candidate, which was argued to have essentially given the presidency to Bush.

He didn’t reveal who he voted for in the Connecticut primary, but believes Sanders could beat Trump more easily than Clinton when it comes to the presidential vote.

“He doesn't produce gaffes,” Nader said of Sanders. “He's very consistent and he's scandal-free. What politician 35 years in office is scandal-free?"